Abstrait

Potential of Ocean Calcifiers to Sequester Atmospheric Carbon in Quantity and Even Reverse Climate Change

David Moore*, Matthias Heilweck, William Burton Fears, Peter Petros, Samuel J Squires, Elena Tamburini and Robert Paul Waldron

Today’s marine calcifiers (coccolithophore algae, Foraminifera [protists], Mollusca, Crustacea, Anthozoa [corals], Echinodermata and some annelids) convert atmospheric carbon dioxide (CO₂) into the solid calcium carbonate (CaCO₃) shells which are left when they die. These organisms could be the biotechnological carbon capture and storage mechanism to control climate change. Two criticisms of this are: (i) ocean acidification has allegedly been shown to cause reduced shell formation in calcifiers; (ii) the calcification reaction that forms CaCO₃ crystals is alleged to return CO₂ to the atmosphere. Here, we review evidence about such criticisms and find reasons to doubt both. Experiments showing ocean acidification is damaging to calcifiers have all used experimental pH levels that are not projected to be reached in the oceans until the next century or later; today’s oceans are alkaline. Claiming precipitation of CaCO₃ by calcification as net source of atmospheric CO₂ might be true in open water environments in equilibrium with the atmosphere. Living calcifiers do not carry out the calcification reaction in such environments. Life’s chemistry is specifically isolated from open water; taking place on enzymatic polypeptide surfaces, within organelles with ion-selective phospholipid membranes, contained in a cell enclosed by phospholipid bilayer membranes. Ignoring what is known about the biology, physiology, and molecular biology of living calcifiers leads to erroneous conclusions and deficient advice about the potential for calcifier biotechnology to contribute to atmosphere remediation. We conclude that the world’s aquaculture industries already operate the biotechnology that, with massive and immediate global expansion, can sustainably control atmospheric CO₂ levels at reasonable cost.